I have two new hives each about 3 weeks old. The queens are laying nice patterns of brood and have filled about 3 frames with brood and some honey. In addition the bees have used an additional 2-3 frames for honey and pollen storage. They have drawn out another two with comb.There are still about two frames in each hive that have no activity. My question is, When should I add a second brood chamber, and when I do, should I put a full 10 frames in it?